The present disclosure relates to post-processing devices mounted to image forming apparatuses, such as copiers and printers, and configured to apply staples to paper sheets and image forming apparatuses with the same.
There are known post-processing devices configured to subject to post-processing, such as stapling, paper sheets having images formed thereon by an image forming apparatus. In such a post-processing device, a stack of paper sheets loaded on a dedicated tray provided inside the device is shifted in a width direction of the stack by a sheet stack shifting section and thus collectively aligned and the aligned stack of paper sheets is then subjected to a stapling process by a stapler. In the stapling process, the stapler applies staples to a plurality of locations on the stack of paper sheets by first applying a staple to one location on the stack, then moving in the width direction of the stack, then applying a staple to the next location on the stack, and thereafter repeating the same procedure. After the stapling, the post-processing device allows the sheet stack shifting section to shift the stack of paper sheets to a predetermined discharge position and discharges the stack toward an output tray provided outside the device.